• Journal of the Korean Wood Science and Technology
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• 제32권5호
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• pp.1-11
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• 2004

국내에서 성장하고 있는 소나무재(Pinus densiflora Sieb. et Zucc)와 이태리포플러재(Populus euramericana Guinier)에 제1인산암모늄(monoammonium phosphate, MAP)과 붕산(boric acid)을 혼합 약제로 처리하여, 난연재이면서 방부재인 처리재를 백색부후균(Trametes versicolor)과 갈색부후균(Tyromyces palustris)으로 부후시켜 처리재와 무처리재의 종압축강도를 측정하고 주사전자현미경으로 판독하였다. 무처리재보다 처리재의 비중과 압충강도가 높은 것을 알 수 있었고 수종별에 따르면 이태리포플러재보다 소나무재의 비중과 압축강도 역시 높은 것으로 나타났다. 그리고 주사전자현미경의 사진상에서 무처리재와 약품처리재에 T. versicolor균과 T. palustris균으로 부후시킨 결과 부후가 진행됨에 따라 무처리재가 처리재보다 세포벽의 파괴가 현저함을 보여 주었고, 또한 T. versicolor균과 T. palustris균의 부후성을 보면 T. palustris균의 목재 열화가 다소 증가하였다.

• 대한영양사협회학술지
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• 제8권4호
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• pp.333-341
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• 2002

Obesity, a state of having excessive body fat enough to attack one's health, is most blamed for causing chronical degenerative illness such as hypertension, diabetes mellitus as well as arteriosclerosis. According to many studies, the program for the weight control was the most demanded at the worksites. This study was designed to investigate the correlation between the degree of obesity and blood parameters of the employees at the worksites. The results of periodic medical examination for 571 employees(male: 418, female: 153) were analyzed; Age, BMI, systolic blood pressure(SBP), diastolic blood pressure(DBP), hemoglobin(Hb), fasting blood sugar(FBS), total-cholesterol(TC), serum glutamic oxaloacetic transaminase (sGOT), serum glutamic pyruvic transaminase(sGPT) and $gamma$-glutamyl transpeptidase($gamma$-GTP). Pearson correlation coefficient was used to find out the correlation between BMI and each blood parameters. In the case of male, 27.3% of the subjects were over-weight. The subject's age and their blood levels of uric acid, FBS, sGOT and sGPT did not show any significant difference regardless of BMI's, while SBP, DBP, Hb, TC and $gamma$-GTP levels of the overweight group were significantly higher than those of normal group. In the case of female, 9.2% of the subjects were over-weight. This study shows that the implementation of weight control program is required at the worksites

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.227-232
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• 2002

To evaluate the practical application of oyster shells as construction materials, an experimental study was performed. More specifically, the long-term mechanical properties and durability of concrete blended with oyster shells were investigated. Test results indicate that long-term strength of concrete blended with 10% oyster shells is almost identical to that of normal concrete. However, the long-term strength of concrete blended with 20% oyster shells Is appreciably lower than that of normal concrete. 1'hereby, concrete with higher oyster shell has the possibility giving a bad influence on the concrete long-term strength. Elastic modulus of concrete blended with crushed oyster shells decreases as the blending mixture ratio increases. Namely, the modulus is reduced by approximately 10∼15% when oyster shells are blended up to 20% replacing the fine aggregate. The drying shrinkage strain increases as the blending ratio increases. In addition, the existing model code of drying shrinkage does not coincide with the test results of this study. An adequate prediction equation needs to be developed. The utilization of oyster shells as the fine aggregate in concrete has an insignificant effect on freezing and thawing resistance, carbonation and sulfuric acid attack of concrete recycling. However, water permeability is considerably improved.

• International Journal of Concrete Structures and Materials
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• 제6권3호
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• pp.145-153
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• 2012

The aim of this study is to explore the possibility of re-cycling a waste material that is now produced in large quantities, while achieving an improvement of the mechanical properties and durability of the mortar. This study examines the mechanical properties and the durability parameters of mortars incorporating plastics bag wastes (PBW) as fine aggregate by substitution of a variable percentage of sand (10, 20, 30 and 40 %). The influence of the PBW on the, compressive and flexural strength, drying shrinkage, fire resistance, sulfuric acid attack and chloride diffusion coefficient of the different mortars, has been investigated and analyzed in comparison to the control mortar. The results showed that the use of PBW enabled to reduce by 18-23 % the compressive strength of mortars containing 10 and 20 % of waste respectively, which remains always close to the reference mortar (made without waste). The replacement of sand by PBW in mortar slows down the penetration of chloride ions, improves the behavior of mortars in acidic medium and improves the sensitivity to cracking. The results of this investigation consolidate the idea of the use of PBW in the field of construction.

• Advances in concrete construction
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• 제10권2호
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• pp.171-183
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• 2020

The main objective of this study is the assessment of the ability of limestone mortars to resist to different chemical attacks. The ability of polypropylene (PP) fibres waste used as reinforcement of these concrete materials to enhance their durability is also studied. Crushed sand 0/2 mm which is a fine limestone residue obtained by the crushing of natural rocks in aggregates industry is used for the fabrication of the mortar. The fibres used, which are obtained from the waste of domestic plastic sweeps' fabrication, have a length of 20 mm and a diameter ranging between 0.38 and 0.51 mm. Two weight fibres contents are used, 0.5 and 1%. The durability tests carried out in this investigation included the water absorption by capillarity, the mass variation, the flexural and the compressive strengths of the mortar specimens immersed for 366 days in 5% sodium chloride, 5% magnesium sulphate and 5% sulphuric acid solutions. A mineralogical analysis by X-ray diffraction (XRD) and a visual inspection are used for a better examination of the quality of tested mortars and for better interpretation of their behaviour in different solutions. The results indicate that the reinforcement of limestone mortar by PP fibres waste is an excellent solution to improve its chemical resistance and durability. Moreover, the presence of PP fibres waste does not affect significantly the water absorption by capillarity of mortar nether its mass variation, when exposed to chloride and sulphate solutions. While in sulphuric acid, the mass loss is higher with the presence of PP fibres waste, especially after an exposure of 180 days. The results reveal that these fibres have a considerable effect of the flexural and the compressive behaviour of mortar especially in acid solution, where a reduction of strength loss is observed. The mineralogical analysis confirms the good behaviour of mortar immersed in sulphate and chloride solutions; and shows that more gypsum is formed in mortar exposed to acid environment causing its rapid degradation. The visual observation reveals that only samples exposed to acid attack during 366 days have showed a surface damage extending over a depth of approximately 300 ㎛.

• 한국구조물진단유지관리공학회 논문집
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• 제12권1호
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• pp.57-64
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• 2008

일반적으로 강재시설물에 사용되는 유기에폭시 도장의 경우, 일반적인 조건에서는 우수한 내구성을 보이고 있으나, 송/배전 시설물인 강재전력시설물과 같이 빛(자외선)이나 열에 노출되는 환경에서는 도막자체의 열화현상에 의한 피해가 더욱 심각하게 증가하고 있다. 본 연구의 목적은 무기계 액상 규산질을 기초로 한 강재용 도장제를 개발하는 것이다. 이를 위해 6가지 예비실험을 거쳐서 최적의 배합조건을 도출하였으며, 물리적 특성실험 및 내구성 실험을 수행하였다. 실험결과 개발된 무기계 도료는 현재의 유기계 도료의 성능을 확보하고 있었으며, 내화학성에 대한 저항성이 개선된다면, 강재 시설물의 대체 도료로 사용될 수 있으며, 그 적용성이 더욱 증가할 것으로 평가되었다.

• 한국축산식품학회지
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• 제36권6호
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• pp.791-798
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• 2016

Free radicals may attack cells or tissue, leading to chronic diseases, and antioxidant consumption is potentially useful for removing free radicals. Egg proteins may be used as potential sources of antioxidant considering their ability of scavenging free radicals to apply for food or cosmetics industry. In this study, we obtained a natural antioxidant protein from fertilized eggs, which was a dietary supplement in some Asian countries. Meanwhile, antioxidant activities of these proteins were evaluated using different oxidation systems. With increasing incubation time, the antioxidant activity of these proteins increased during 15 d of incubation. The samples on day 15 were performed for isolation of antioxidant protein. The protein, named P4-1 (MW, 45 kDa), was isolated and purified by consecutive chromatographic methods. P4-1 contained 17 amino acids, which was determined by liquid chromatography-mass spectrometry and Amino Acid Analyzer. Moreover, the amino acid sequence was highly similar to that of ovalbumin. Differential scanning calorimetry showed that the denaturation temperature of P4-1 was $57.16^{\circ}C$. Furthermore, P4-1 suggested high oxygen radical-absorbance activity in ${\cdot}OH$ assays, and its antioxidant activity was stable at $30-50^{\circ}C$ in acidic and neutral pH. Thus, these results revealed that P4-1 may be a potential resource as a natural antioxidant.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2019년도 추계학술대회
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• pp.88-88
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• 2019

Antioxidants are involved in the defense mechanism against the attack of free radicals. This study was carried out to determine the antioxidant activity of new variety of Glycyrrhiza cultivar radix, Wongam and Sinwongam. Dissolved freeze dried Wongam and Sinwongam extracts were filtered by $0.2{\mu}m$ filter and serially diluted at the concentrations of $10{\mu}g/mL$, $50{\mu}g/mL$, $100{\mu}g/mL$, $500{\mu}g/mL$, and $1000{\mu}g/mL$. The antioxidant potential was determined by DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, ABTS (2,2-azino-bis (3-rthylbenzthiazoline-6-sulfonic acid) diammonium salt) radical cation decolorization assay, nitrite radical scavenging assay, and ferric reducing antioxidant power (FRAP) assay. DPPH radical scavenging activities (i.e. the highest value $50.9{\pm}0.8%$ by Wongam and $82.6{\pm}1.1%$ by Sinwongam), ABTS radical scavenging activities (i.e. the highest value $88.1{\pm}1.8%$ by Wongam and $98.6{\pm}0.1%$ by Sinwongam), and nitrite radical scavenging activities (i.e. the highest value $87.3{\pm}1.6%$ by Wongam and $89.8{\pm}0.8%$ by Sinwongam) increased in a dose-dependent manner. In addition, ferric reducing power activities also increased in a dose-dependent manner. The FRAP value of Wongam and Sinwongam extracts were $0.72{\pm}0.03$ and $0.99{\pm}0.06$ compared to ascorbic acid, as a positive control, was $1.32{\pm}0.02$. These results suggested that Wongam and Sinwongam have beneficial effects as a potent antioxidant.

• Journal of Korean Neurosurgical Society
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• 제39권1호
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• pp.36-39
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• 2006

Objective : The present study attempts to address the change of management results over time during the past 13 years in good-grade patients with intracranial aneurysm. Methods : Six hundred twenty five [Hunt-Hess grade I to III] out of 826 patients with ruptured intracranial aneurysms operated by the same operator within 3 days after the attack from 1990 to 2002 were selected. Since 1998, endovascular aneurysmal occlusion was done in selected cases of 21 patients. The change of management results over time, including rebleeding rate, delayed ischemic neurologic deficit[DIND] as a cause of morbidity and mortality and surgical outcome were examined. Results : The ratio of poor-grade patients in all patients tended to decrease over the years. The early rebleeding rate declined from 5.0% to 1.2% with the use of tranexamic acid and computed tomography angiogram DIND as a cause of mortality and morbidity has decreased from 12.5% in 1990 to approximately 0% currently. Surgical outcome began to improve significantly in 1994 [poor outcome : 25% in 1990, 12.2% in 1994,6.8% in 2002]. Conclusion : These results suggest that the advances in care and increased experience of the operator significantly affect the change of overall outcome, and early detection of the aneurysm is needed for reducing the ratio of poor-grade patients.

• 콘크리트학회논문집
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• 제20권4호
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• pp.439-449
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• 2008

혼화재를 사용한 혼합콘크리트는 콘크리트의 품질을 개선시키며 지속가능한 콘크리트구조물의 건설에도 기여하고 있다. 실리카퓸 (SF), 고로슬래그미분말 (GGBS), 플라이애쉬 (PFA) 등의 시멘트계 결합재는 고성능콘크리트의 혼화재로서 인식이 증가되고 있으나, 삼성분계 혼합콘크리트에 대한 연구는 매우 제한적이며, 특히 염해에 의한 부식저항성 측면에서의 연구는 상당히 취약한 실정이다. 본 연구에서는 보통포틀랜드시멘트의 경우를 50%의 치환율로 고정한 후 고로슬래그미분말의 경우는 $20{\sim}40%$, 실리카퓸의 경우에는 $5{\sim}15%$, 플라이애쉬의 경우는 $10{\sim}45%$로 치환한 경우의 각종 배합에 의한 염해부식저항성에 관한 실험연구를 수행하였다. 삼성분계 혼합콘크리트의 염해부식저항성을 평가한 본 연구에서는, 수행 실험으로서 부식 저항성 실험, 염소이온 고정화 능력 실험, 급속 염화물 촉진 실험, 산중성화 저항 능력 실험 등을 수행하였다. 연구 결과로서, 삼성분계 콘크리트는 미세구조를 치밀화 하여 염소이온의 이동을 지연시키고 있음을 확인하였다. 또한, 염분을 함유한 삼성분계 혼합콘크리트 내의 염소이온 고정화 능력 및 산중성화 저항 능력이 크게 개선되고 있음을 확인하여 염해에 대한 부식 저항성이 향상됨을 알 수 있었다.